As evidence of the negative effects of environmental tobacco smoke (ETS) has mounted, an increasingly popular public policy response has been to impose restrictions on smoking through 100% smoke-free bans. The Centers for Disease Control and Prevention (CDC) and the Institute of Medicine (IOM), amidst evidence that smoking bans reduce smoking prevalence and adult non-smokers' exposure to ETS, recommend that states and localities enact complete bans on smoking in all non-residential indoor locations, including worksites, restaurants, and bars. However, a key link necessary for a comprehensive evaluation of the effectiveness of smoking bans has been missing from the literature including the CDC and IOM reports. Specifically, it is not known whether and to what extent smoking bans at the state and local levels impact the health of children and infants. The rationale for smoke-free laws implicitly presumes there are public health gains from reducing adult cigarette consumption and declines in adult ETS exposure that extend to children. The presumption that these gains, a priori, will extend to infants and children may or may not be correct. On the one hand, decreases in adult smoking prevalence as a result of the smoking bans may reduce ETS exposure among children, infants, and pregnant women. However, if smokers shift from consuming cigarettes at 100% smoke free work and other public places to smoking at home (when children, infants, or pregnant women are present) then these policies may have a harmful effect on children and infants. Such compensatory behavior by smokers can potentially increase the prevalence of smoking at home and lead to higher ETS exposures among children. Without information on the link between smoking bans, potential shifts in smoking to the home, and the impact on child and infant health, either the costs or benefits of interventions banning smoking may be understated, which in turn may skew the proper evaluation of such policies. The proposed study aims to address this critical gap in the literature and provide the first estimates of how 100% smoke-free regulations impact the venue of smoking and how they impact the health of children and infants. The study will match information on all local and state-level 100% smoke-free legislation by type (workplace, restaurant, and freestanding bar) and other tobacco-control policies to parent and child records from the National Health Interview Surveys (NHIS) and birth records from the U.S. Natality Files (NF). Both datasets are nationally-representative and have large sample sizes, thus maximizing statistical power and precision, and allowing an assessment of differential effects across various socio-economic factors. The NHIS includes information on ETS-related measures of adverse respiratory health and the NF includes information on birth- weight and gestation, both of which have been found to be impacted by own smoking and ETS exposure. The estimates from the proposed research will address the missing link in the literature and provide valuable inputs towards a comprehensive evaluation of state and local restrictions on smoking in various venues. PUBLIC HEALTH RELEVANCE: The proposed study seeks to improve the understanding of 100% smoke-free laws and the impact of these laws on the health of children and infants. Currently, such benefits are presumed to extend to children and infants, without any directly-bearing evidence, since the literature has found support of positive health effects for adults in various settings. A comprehensive evaluation of 100% smoke-free laws cannot be completed without understanding the impact of these laws on infant and child health.